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the reference point. If SGC notifies the WQCD that they intend to perform additional <br /> remediation projects, then SGC will submit work plans within 60 days of the <br /> notification or within a reasonable time frame based on the accessibility of a site for <br /> planning and the complexity of the project. The project will be constructed during <br /> the first full construction season which is available after submission and approval of <br /> the Work Plan. <br /> 2. Comment: Pages 4.a. and S.a.: The copy of Appendix A we received had several <br /> blanks referencing the paragraphs in the Consent Decree. These blanks need to be <br /> completed. <br /> Response: These blanks have been completed, with paragraph numbers 13, 14, and <br /> 8, respectively. <br /> APPENDIX B TO CONSENT DECREE <br /> 1. Page 1.b, Part B=2(1), Sunnyside Mine Pool, The plan calls for raising the pH in the <br /> Sunnyside Mine to a range of 8 to 9. We are concerned that the range of pH may not <br /> be high enough to handle the zinc and copper concentrations. A pH range of 10 to <br /> 11 would appear to be a more realistic range to assure adequate precipitation of <br /> metals within the mine pool. There is no indication as to how the pH for the injection <br /> or the pH in the mine pool will be monitored and adjusted. Either there should be a <br /> requirement for monitoring the mine pool in sufficient locations to assure that the pH <br /> is in the target range or the concentration at the point of injection should be specified. <br /> The concentration at injection should be sufficiently high to achieve the ultimate range <br /> of pH throughout the mine pool at equilibrium. <br /> Response: The alkaline injection project will target a pH of 9.0 to 10.0 in the mine <br /> pool. The injection pH will be periodically adjusted based on benchscale testing to <br /> achieve a target injection pH level of 12.0. In addition, to extend the period during <br /> which alkaline injection is possible, the point of injection has been relocated to the <br /> pipe through the bulkhead seal within the Terry Tunnel. <br /> 2. Comment: Pages 1.b, 2.b and 3.b: The plans for mine waste dumps and tailings <br /> removals do not mention removal of the contaminated material underlying the waste <br /> rock or tailings. Experience at the Eagle Mine and Chalk Creek indicates that a <br /> significant amount of contaminated soil will be under the piles. This should be <br /> removed and new soil should be placed in the excavation prior to any attempt at <br /> revegetation. If this does not happen, the revegetation effort will be subject to failure <br /> and the groundwater and surface water leaving this area will show a significant <br /> increase in metals. These projects should be undertaken with specific soil sampling <br /> plans and removal criteria to assure that the highest level of metals contaminated <br /> material is removed. Criteria for soil cover after removal of the material should also <br /> 9 <br />